Researchers from the University of Aberdeen are part of a major new clinical trial aimed at reducing the use of street-sourced benzodiazepines among people receiving treatment for opioid dependency.
Led by the University of Stirling, the three-year study, funded by the National Institute for Health and Care Research (NIHR), is to be conducted across seven sites in Scotland and England, beginning in January, and is one of the first of its kind.
The University of Aberdeen Centre for Healthcare Randomised Trials (CHaRT) will support the delivery of the study, including trial management, data management and and statistical analysis.
The study will assess whether prescribing a stable dose of diazepam alongside additional support can help prevent harmful drug use and reduce drug-related deaths.
The launch of the trial has been welcomed by Drugs and Alcohol Policy Minister Maree Todd who said it will provide an evidence base as efforts continue to save and improve lives.
Benzodiazepines are medicines commonly prescribed to treat anxiety and sleep problems in the short term. However, their use alongside opioids such as heroin is widespread among people who use street drugs, and this combination has been strongly linked to the high rate of drug-related deaths.
While opioid dependency can be safely managed through opioid agonist treatment (OAT) with methadone or buprenorphine, there is currently no equivalent treatment for people dependent on benzodiazepines.
This gap in care has contributed to the increasing use of unpredictable and often dangerous street-sourced benzodiazepines, which can contain unknown or highly potent substances, and are associated with blackouts, overdose, and death.
Professor Catriona Matheson, of the University of Stirling’s Centre for Healthcare and Community Research (CHeCR) in the Faculty of Health Sciences and Sport, is leading the study.
She said: “There is a real need for clinically based research within this stigmatised and under-researched population. They should have the same access to evidence-based treatment options available across other areas of healthcare in the UK.
“One of the aims of this research is to address that lack of evidence in such a key area of risk relating to drug-related deaths. It will inform clinical guidance for drug treatment services that have struggled to support people using multiple substances due to the lack of evidence. If successful it will contribute to reducing drug-related deaths, which are a societal challenge.
“Furthermore, the associated health economic analysis will provide evidence of the most cost-effective treatment option. This is essential for ensuring public money is spent appropriately.
“By providing clear clinical and cost effectiveness data our trial will provide commissioners, who are responsible for understanding the local needs for drug treatment and recovery services, and policymakers with direction of what services should be commissioned and how.”
Drugs and Alcohol Policy Minister Maree Todd said: “We want to make sure everyone gets the treatment they need. I welcome this trial, which follows a successful Scottish Government-funded feasibility study. It will help provide an evidence base as we continue to strive to save and improve lives.”
Participants in the trial will be randomly assigned to receive either a new intervention or standard care, which currently involves a reducing diazepam dose over a maximum of six months as per national guidance.
The new intervention combines a steady prescribed dose of diazepam (up to 30 mg) with tailored psychological and harm reduction support addressing underlying causes such as anxiety, trauma, and sleep difficulties.
Over a 12-month follow-up period, researchers will measure the use of high-risk street benzodiazepines through laboratory analysis of mouth swabs and self-reported data on drug use.
Additional outcomes analysed will include overdoses, hospital admissions, mental health measures, cognitive function, and overall treatment acceptability.
The economic impact of the intervention will be determined by examining service use across both study groups, determining whether the approach offers good value for money. Working with a specialist testing centre, the team will monitor emerging synthetic drugs in the street supply to ensure ongoing safety and relevance of testing protocols.
At three and 12 months, participants and clinical staff will take part in interviews to share their experiences and perspectives, helping the researchers understand what makes the new intervention effective, or identify barriers that might limit its success.
Professor Graeme MacLennan, who will lead the Aberdeen components of the study, said: “We are proud to contribute to this important study, which tackles a major gap in treatment for people who use both opioids and street benzodiazepines.
“Through CHaRT’s expertise in rigorous trial design and analysis, we aim to produce robust evidence to support safer and more effective care.
“This research has the potential to reduce harm, save lives, and shape future policy and practice in a critically underserved area of addiction treatment.”
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